1. Technical Field
The present invention generally relates to display technology fields and, particularly to a driving circuit used for a current-driven device and a light emitting device.
2. Description of the Related Art
An organic light emitting diode (OLED) is a type of current-driven device and produces lights with different brightnesses according to currents flowing therethrough. The OLED utilizes transistors cooperative with a storage capacitor to control brightness thereof. Referring to FIG. 1, showing an electrical relationship between an OLED and transistors as well as a storage capacitor associated with the prior art. As illustrated in FIG. 1, a first terminal of the OLED 12 is electrically coupled to a power supply voltage OVDD through a driving transistor M1, a second terminal of the OLED 12 is electrically coupled to another power supply voltage OVSS. Herein, the power supply voltages OVDD and OVSS can be provided by a driving circuit (not shown). The gate of the driving transistor M1 receives a data signal DL through a switching transistor Ms to determine a value of a current flowing through the driving transistor M1, so as to control the brightness of the OLED 12. On-off states of the switching transistor Ms is determined by a scanning signal SCAN electrically coupled to the gate of the switching transistor Ms.
The power supply voltages OVDD and OVSS of the respective first terminal and second terminal of the OLED 12 generally are a positive driving voltage and a negative driving voltage, however the situation of both the two terminals are required to be provided with positive voltages may be encountered in some applications. If the terminals both are provided with positive voltages, since the positive voltages generally are used as power supplies to provide load currents and incapable of providing the function of the load currents flowing back to the power supplies (i.e., current sink), and therefore it is necessary to redesign the driving circuit for providing power supply voltages so that the driving circuit is endowed with functions of voltage stabilization and current sink.